Stencil printing of a highly conductive graphene ink toward flexible electrochemical biosensors for glucose monitoring

Disposable, flexible and low-cost coated biosensor electrode obtained by printing conductive inks presents a great potential as health monitoring devices. A novel and highly conductive coating of graphene ink was printed on a flexible substrate using the stencil method to prepare a sensitive biosensor for enzymatic electrochemical detection of glucose. A novel water-based graphene ink including an acrylic copolymer was formulated in this work. The Sheet resistance was obtained in the range of 42.14 Ω/sq in new formulation of the newly proposed graphene ink to make it a proper candidate for flexible biosensor manufacturing. The sensitivity and limit of detection of 16.42 μA·mM−1·cm−2 and 1.34 mM were respectively achieved for the biosensor in the linear range of <2 mM to >28 mM. The results signified high selectivity against interfering species such as ascorbic acid and lactose, and high repeatability and reproducibility with low relative standard deviation values of 1.04 % and 1.5 %, respectively, for the device. No considerable reduction in the printed electrochemical biosensor (PEB) performance was observed after bending cycles of up to 100, indicating the high flexibility of the biosensor. The PEB presented a great potential to be used as a personalized glucose monitoring device in complex biological fluids.